The Rapture: Christianity's Most Preposterous Belief

There continue to be many questions concerning the "Rapture" of the Church and its apparent contrast with the "Second Coming" of Jesus Christ. Where does this strange view come from? Is the term "rapture" even in the Bible?
Clearly, the idea of the Rapture can be considered the most preposterous belief in Biblical Christianity. The situation regarding the doctrine of the Rapture is painfully similar to the famous quote by Dr. Richard Feynman, speaking of quantum physics:
I think it is safe to say that no one understands quantum mechanics... in fact, it is often stated of all the theories proposed in this century, the silliest is quantum theory. Some say that the only thing that quantum theory has going for it, in fact, is that it is unquestionably correct.